Monerans are one -celled organisms that have been present on earth for about 3.5 billion years. These one celled organisms do not have a nucleus. There are about 1800 species of monerans that have bee named. Monerans are grouped into bacteria and cyanobacteria.

 The protist are a more varied group. Most protist are one-celled, however some are many celled. They are more complex ha the monerans, they have a nucleus that controls the cell's activities. They have been around on earth for about a billion years and there are about 38,00 species identified.  Plants are many-celled organisms. There are about a quater of a million known plant species. The oldest sign of a plant fossil is 400 million years old. photo taken by n.crumpler using digital camera Fungus Kingdom  Fungi may be one-celled or many celled organisms. The are decomposers. Yeast and mold are an example of fungus.   Animal Kingdom  Animals are extremely complex organisms with many cells. Evidence of animals dates as far back as 700 million years. There are about one million known animal species. They vary in shape, size and color. the my have wings and some do not. Some walk on four while others walk on three. Humans, whales, elephants and worms are all examples of this kingdom.